Update 7/17/4:20pm:

Dialpad service is now believed to be restored. Please let us know if you are still experiencing any issues. Thank you.

Original Post 7/17/18 4:08pm:

There is currently intermittent Dialpad service due to an outage with the Google Cloud Platform engine. As 3:58 Google has partially resolved the problem and are working towards a complete resolution for the near future.